Previous research has shown that an illusory correlation -- the perception of an association between two variables that does not exist in the information on which observers' judgments are based - - can be based on the co-occurrence of distinctive stimuli, and that this information processing bias can result in the differential perception of social groups. Recently completed experiments by the principal investigators has found that the nature of these processing biases may differ as a function of the target described in social information -- whether members of groups or individual persons are the units about whom information is being processed. These differences are interpreted in terms of a fundamental distinction between (a) on-line or impression-based processing, which is hypothesized to be characteristic of processing information about individuals, and (b) memory-based processing, which is viewed as typical of information processing about group members. The proposed research program develops and extends this work, testing the implications of this distinction between different modes of information processing for group and individual targets. The research also investigates the consequences of these different modes of processing for how we deal with self-relevant information and for judgments about the self. The results of the proposed research program will be informative about the nature and consequences of certain cognitive mechanisms and biases for perceivers' conceptions of and judgments about various targets of social perception -- social groups, individuals, and the self.